My grandparents gust gave me an interesting item: a US atlas from the early 1960s! I am guessing 1961 based on the interstates it shows as complete. It is incredible to see how different cities look with no (or almost no) interstate infrastructure. Albuquerque looks almost the same, but the familiar interstate crossroads is gone. LA and DFW look like different cities with just the very beginning of there highways having been completed. And DC looks odd not having the 485 loop around it.
Have you ever looked at an old map and noticed a difference right away? What was different about your home town? Did it not exist? Was it bigger back then?
See if you can find something similar for your state to this "Timeline of Iowa's Four-lane highways". It starts with 1956 and continues to now.
https://iowahighwayends.net/maps/fourlanes.html
For me it is also the way the highways are shown on the map. Gousha is no longer around but I thought their style was better than Rand McNally.
Rick
The old atlas at first did not have a good way of representing fully controlled access highways.